---
features:
  - |
    Apache MPM tunable support has been added to the os-keystone
    role in order to allow MPM thread tuning.
    Default values reflect the current Ubuntu default settings:

    .. code-block:: yaml

        keystone_httpd_mpm_backend: event
        keystone_httpd_mpm_start_servers: 2
        keystone_httpd_mpm_min_spare_threads: 25
        keystone_httpd_mpm_max_spare_threads: 75
        keystone_httpd_mpm_thread_limit: 64
        keystone_httpd_mpm_thread_child: 25
        keystone_httpd_mpm_max_requests: 150
        keystone_httpd_mpm_max_conn_child: 0
